Furnace valve construction



Oct. 13, 1953 J. L. ROOF FURNACE VALVE CONSTRUCTION 2 Sheets-Sheet l Filed Aug. l, 1951 INVENTOR.

JAY L. R OO F J. L.. ROOF FURNACE VALVE CONSTRUCTIO N oct.y 13, 1953 2 Shets-Sheet 2 Filed Aug. 1, 1951 INVENTOR. JAY I.. R 00F BY l 6W, MLL M6( I Qtented Oct.. 1s, 1953 2 655 363 wwwmain. The mr@ wm h basi. 119g. as the outgo port; bggrnn th @agg po 1.1. of. tu@ nel a' pgove entswher byt tion of the iiue system and stack of an open hearth furnace, showing a set of reversing valves and a stack damper embodying my invention, the plane of section being indicated at I--I in Fig. 2 of the drawings;

Fig. 2 is a vertical, sectional view of the flue system and valves, vas seen on the planes II-II of Fig. 1;

Fig. 3 is a vertical, sectional view of the installation, as seen on the plane III-III of Fig. l;

Fig. 4 is an isometric View of one of the seats of the reversing valves; and

Fig. 5 is a fragmentary view showing one of the reversing valves as shown in Fig. 1, but to larger scale. Y

Referring to the drawings the two regenerators of an open hearth furnace are fragmentarily shown at 2 and 3, connected by regenerator lues 4 and 5, respectively, to a` flue 5 that opens into the bottom of a stack 1. Such flue system is conventionally constructed of concrete 8, lined with refractory brickwork 9. Y,

The valve system of the furnace comprises a reversing valve I controlling communication between regenerator flue 4 and stack flue 6, a reversing valve II controlling communication between regenerator flue and the stack flue, and a stack valve I2 controlling A,communication between the stack 'I' and both regenerator flues 4 and 5. Above the flues at the point where the stack flue 6 merges with the regenerator flues 4 and 5, an air-box I3 is provided, and from such air-box a duct I4 leads to a powerfully drivenv fan or blower (not shown) that delivers air into the box. In one side wall of the air-box a re- Y movable door I4a is provided, and this door may be opened in the event of fan failure, to admit air to the box from the outer atmosphere.

The reversing valves IG and II, and the stack valve or ldamper I2 are mounted for vertical travel on valve seats I5, I6 and I'i, respectively. In Fig'. 4, the structure of the valve seats I5 and I6 will be readily understood. Each of such seats comprises a hollow metal frame, having a central body portion I8, and two marginal anges I9, I9. In service such valve seats are mounted in inclined position, as shown in Fig. 2, and the central body portion I8 provides the seat proper, upon which a valve (Il) or Il) is adapted to slide upwardly and downwardly, laterally guided and held in place by and between the two marginal flanges I9, I9. The central body portion I8 includes two windows and 2l, resulting in the body portion I8 actually comprising two vertical edge portions 22 and 23 that are laterally connected by horizontal portions 24, 25 and 25. The portions 22 to 26 form the seat upon which the Vvalve is adapted to seat and vertically to slide.

The valve seats I5 and I6, each constructed as shown in Fig. 4, are incorporated and sealed in 4 but known to the art. Upon reference to Fig. 2 it will be understood that each of the valves I0 and I I may be vertically adjusted on its inclined seat, between a position in which one of the windows 20 and 2I in the seat is open and the other closed.

In Fig. 2 the valve II) is shown in its lower position, closing the lower window 20 in its seat, and thus blanking communication between regenerator flue 4 and stack flue 6, and leaving the upper window open so that air may flow from the air-box I3 to the said flue 4, whence such air streams through the regenerator 2 (Fig. 1)

and is preheated for sustaining combustion of fuel delivered to the corresponding port of the furnace, which is then serving as the firing port. At this time the valve I I is sustained in elevated position on its seat, closing the upper window 2| and blanking the passage between the airbox I3 and regenerator iiue 5, while leaving the lower window 20 open, and letting flue 5 stand in open communication with the stack iiue 6 (Fig. 1), whereby under the suction or draft of the stack the hot products of combustion are drawn through regenerator 3 from the associate furnace port, which is then serving as the outgo port. Thus, the valves I0 and II remain positioned until the regenerator 2 has yielded most of its effective heat to the combustion air and the regenerator 3 has received a store of heat from the products of combustion. Then, the furnace is Y reversed; that is, the iiow of fuel is cut-off from the ring port of the furnace and delivered to the port which had been serving as the outgo port; and substantially simultaneously with this fuel reversal the positions of the valves I5 and I I are reversed-the valve I0 is raised to open window 20 and close window 2I in its seat I5, and valve I l is lowered to open window 2l and close window the flue and air-box structure, in the mutually inclined positions shown in Fig. 2. The lower windows 20 of the seats are arranged to define the lines Yof flow between the regenerator ues 4 and 5, respectively, and the stack iiue 6, while the upper windows 2| Vof the two seats are arranged respectively to defineV the lines of flow from within the air-box I3 to the iiues 4 and 5. Each of the valve-and-seat assemblies I0, I5v and II, I6 are enclosed and hermetically sealed -to the air-box and the respective iiues 4 and 5 by means ofhoods 21 of steelY plate, and from the top of each valve I0 and II a rod 28 extends upwardly through the associate hood, and is connected to a suitable valve-adjusting mechanism, not shown 20 in its seat I5.Y Manifestly, such reversal of the positions of the valves I0 and I I permits combustion air to flow from the air-box I3 through iiue 5 and regenerator 3 to the port of the fur'-v nace which has become the firing port, while the hot products of combustion are drawn from the opposite port of the furnace through the regenerator 2 andlues 4 and 6 to the stack. In such way afurnace equipped with reversing valves is operated, and the reversal of the furnace is repeated as need be during furnace operation.

The stack valve or damper I2 is adjustable on its seat I1 to regulate the area of the stack flue 6 and the degree of the stack draft effective upon the furnace. The particular construction of the stack damper and its seat will be considered later herein.

The reversing valves and .their seats are hollow, constructed of metal, preferably steel or iron, and provision is made for a flow of cooling air through the hollow bodiesV of the valves and seats, to dissipate heat and safeguard them against the high temperatures to which they are exposed in service. The construction and arrangement of the Vvalves and seats with the ue system and air-box Yback-wall of each valve, the back-wall being the A wall lthat bears and slides upon the vassociate valve seat. Adjacent the bottom edge of each A Vvalve one or more outlets 30 are formed in the front wall of the valve. It will be perceived that the upper ports or windows 2 I, in the valve seats I5 and I6* areso extended' vertically that, no matter whether the: valves I: and. II: are raised or lowered (cf. the positions of the two valves in 2)?, the inlets 29` stand open communidir tien withV the Aair-box I3, whereby air? `ii QQnr tnuously red, into the hollow valve bodies; under the: super-atmospheric pressure oli the conventional combustion air fan not shown);` which feeds the air-box. When a valve is in raised position (cf. valve Il, Fig. 2) the outlet 30 of the valve is exposed to the stack draft then effective in iiues and E. On the other hand, when the valve is in its lowered position, closing the lower window 2|) in its seat (cf. valve II), Fig. 2) the outlet 30 is exposed to the suction effect of the stream of air drawn from the air-box I3 and through flue 4 and regenerator 2 into the furnace. Thus, it will be understood that cooling air continuously flows through the hollow bodies of the valves under the effect of stack draft or suction, augmented by the positive pressure at which the air is delivered to the air-box.

Referring to Figs. 4 and 5, it will be understood that air inlets 3I are provided in the top and center cross members 25 and 2B, respectively, of each valve seat, and outlets 32 are provided in the lower cross member 24. Regardless of the position of either valve on its seat air under pressure in the airbox I3 enters the hollow body of the seat, and iiows in the directions of the arrows in Fig. 4 to the outlets 32, which are constantly exposed to the suction effect of the stack draft prevailing in flue 6. As the arrows indicate, a uniformly distributed flow of air is maintained throughout all portions of the hollow body of the Valve seat, thereby dissipating the heat to which the structure is subjected during furnace operation. The Valve seats, as thus cooled by an injected and drafted circulation of cooling air, in combination with the air cooled valves, provides a reversing valve installation that avoids the expensive use of cooling water.

It is to be noted that air cooled valve seats in accordance with my invention may be employed with air cooled valves of the type disclosed in my Patent No. 2,285,533. Furthermore, the aircooled valve and seat structure of the invention may be used in the flue systems cf furnaces using other forms of heat-exchangers than regenerators, and in llues other than stack flues.

The stack valve or damper I2 and its seat Il may both be air cooled in accordance with my invention. The air outlet 3!! (Fig. 3) of the damper I2 is constantly exposed to the draft or suction prevailing in the stack flue 6, and under such suction air is drawn through an inlet 33 from the outer atmosphere, and, sweeping through the hollow body of the damper, safeguards the damper from injury due to heat. The damper seat II is generally similar in structure to the seats I5 and I6, save that the seat I'I need have only two hollow cross members 24a and 25a. From the cross member 25a the seat is continued upwardly in two hollow side portions Ia of L- shape in cross section. These hollow side portions are open at their upper ends, forming air inlets, while air outlets 35 are formed in the cross members 24a and 25a that stand in open communication with the stack flue E, with the consequence that cooling air is sucked from the outer atmosphere downwardly through the hollow body of the damper seat into the flue Ii. A continuous flow of cool air through the damper and its seat is maintained, andthe cbjectsoi theA pventibn are realized.

1 In` the: appended claims the term stack flue" willrw be unclerstvrxid;r to include a flue leading to an exhaust fan or other* outlet than a stack, and

the terms "duct"`or flue duct indicate the two itwill be` noted that within the term-s of the claims various changes and modifications will occur" te tfhoseyslcll'l'ed in the art without departingr the `spl-rit of the invention.

I claim:

1. In a reversing valve system having two flue ducts communicating with a stack iiue and `having an air box for supplying air under pressure to a selected one of said flue ducts, the invention herein defined comprising a pair of hollow valve seats each having two spaced parallel side guides and three hollow cross members connecting the side guides, one of the cross members being located near each end of the guides and the third one being intermediate the ends of the guides, the hollow interiors of the guides and cross members all being in continuous communication whereby each seat is provided with a window-like air port between the intermediate cross member and one of the end cross members and a window-like hot gas port between the intermediate and other end cross member, said seats being positioned across the ends of the air box with the air ports thereof registering with the air box and with the gas ports thereof being positioned between one of said ue ducts and the stack flue, the intermediate and end cross frame member defining the air port having openings in the confronting surfaces thereof which are always open to the air in said air box, the third cross member hav ing an opening therein leading from the interior thereof to the gas port of which it constitutes one boundary, and a plate-like valve slideable on each valve seat between said guides on the face of the seat which is turned away from the air box and selectively movable from a position over one window-like port to a position over the other.

2. A reversing valve structure as defined in claim 1 wherein each plate-like valve is a hollow body having opposed face plates, one of which rests against the seat, the valve body being of a length such that when it completely closes the gas port it projects part-way across the air port, said face plate which is against the valve seat having an opening therein which is only in said part of the valve that always projects across the air port and which is of sufficient length to be exposed to the air port when the valve is in position to close either port, the hollow valve body having an opening therethrough adjacent its opposite end in the opposite face thereof.

3. A reversing valve system comprising two separate ducts opening into a stack iiue and an air box adjacent the stack ilue for selectively delivering air to either duct, a continuously hollow metal valve seat extending across each of said first ducts and across opposite ends of the air box and having a pair of window-like ports therethrough, one of which registers with its respective duct and one of which registers with an end of the air box, a hollow valve plate slideable on each valve seat on that face of the seat which is faced away from the air box, each valve being selectively movable from a 'position to cover either of said window-like ports and open the other, said hollow valve seat and valve each having air inlet openings opposed to the air in Said air box, and having air outlet openings therein adjacent those points thereof which `are most remote from the air inlet openings and which air outlet openings are a1- Ways open to the gas stream owing in the sev-f eral ducts and the flue whereby a continuously forced circulation of cooling air is at al1 times provided through the Valve seats and valves from the air box through the hollow valves and seats. JAY L. ROOF.

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References cited in the me of this patent UNITED STATES PATENTS Number 5 Name Date V Henry Dec. 24, 1935 Roof Feb. 28, 1939 Forter Nov. 14, 1939 Roof June 9, 1942 Hellan Aug. 8, 1950 

